Always start with the pinout. Never throw parts at a diesel ECU until you verify voltage, ground, and signal at the pins. Part 8: Wire Color Variations (Prado vs. Hiace vs. Surf) Toyota changed wire colors slightly by model:
No start but cranking? Check Pin B1 (crank sensor) resistance should be 1.6–2.1 kΩ. If open, the ECU never fires the injectors. Connector C – Outputs & Communications (16P) | Pin | Wire Color | Function | Notes | |------|-------------|---------------------------|------------------------------| | C1 | Black | TC terminal (check engine light) | Switched ground – illuminates when fault exists | | C2 | White | Tachometer output | 12V square wave (diesel tach) | | C3 | Green | AC idle-up request | 12V when AC compressor on | | C5 | Orange | Diagnostic (SIL) | 9600 baud for Toyota scanner | | C6 | Blue/Red | EGR vacuum switching valve (VSV) | 12V control | | C9 | Yellow | Immobilizer communication (if equipped) | Serial data to transponder amp | | C10 | Brown/Red | Fuel heater relay | 12V below 5°C | | C12 | Pink | Idle-up VSV for power steering | 12V at steering load | 1kz ecu pinout
Always confirm pin position by number, not color alone. The pinout’s position is consistent; the wire color is a guide. If you’re building an off-road buggy or custom 4×4, you might need to depin the ECU connectors. Always start with the pinout
Terminal release tool (small flathead), replacement pins (from Toyota or Ballenger Motorsports), and the official Toyota Electrical Wiring Diagram (EWD). Hiace vs
Pin A3 (ground) corrodes. Symptoms include random stalling and low injection pump pressure. Connector B – Sensor Inputs (22P) | Pin | Wire Color | Sensor | Signal (Key ON) | |------|-------------|---------------------------|------------------| | B1 | Red/Blue | Crankshaft position (NE) | AC 0.5-1.0V (cranking) | | B2 | White/Blue | Camshaft position (G signal) | AC 0.5-1.0V | | B4 | Yellow/Green | Throttle position sensor (VTA) | 0.5V idle – 4.5V WOT | | B6 | Brown/White | Engine coolant temp (THW) | 2.5V cold – 0.2V hot | | B7 | Green/Black | Intake air temp (THA) | 3.0V cold – 1.0V hot | | B9 | Pink/Blue | Boost pressure sensor (PIM) | 1.0V at 0 psi – 3.5V at 15 psi | | B13 | Violet/White | Vehicle speed sensor (SPD) | 0-5V pulse (AC) | | B18 | Blue/Yellow | Neutral start switch (NSW) | 0V in Park/Neutral; 12V in gear | | B20 | Gray | EGR lift sensor | 0.5-4.5V |